Thermal spray coating apparatus

Abstract

A thermal spray apparatus for depositing a coating on to a substrate is provided which includes a plasma generator for selectively changing gas from a gaseous state to a plasma, and apparatus for filtering plasma. Powder particles entrained in the plasma change from a solid state to a molten state. The apparatus for filtering the plasma permits only a high intensity region of the plasma to pass through to the substrate.

We claim: 
     
       1. A thermal spray apparatus for depositing a coating onto a substrate, comprising: a plasma generator, wherein said generator selectively changes gas from a gaseous state to a plasma; and   means for entraining powder particles in said plasma, wherein a portion of said powder particles change into a molten state while entrained within said plasma; and   a plasma filter, disposed adjacent the substrate, for filtering said powder particles entrained within said plasma;   wherein plasma and entrained powder particles exiting said plasma generator travel between said plasma generator and said plasma filter, and said plasma filter is sized to permit only a high intensity region of said plasma and entrained molten powder particles through to the substrate.   
     
     
       2. A thermal spray apparatus for depositing a coating onto a substrate according to claim 1, wherein said said plasma filter comprises a body with an aperture; wherein said high intensity region of said plasma and entrained molten powder particles pass through said aperture.   
     
     
       3. A thermal spray apparatus for depositing a coating onto a substrate according to claim 2, wherein said body of said plasma filter is formed to collect powder particles not permitted through said aperture.